linux-kernel - Re: [PATCH 4/4] usb: typec: tcpci: add support to set connector orientation

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Message-ID: <20240205173242.z56gbx2agwef3ufu@pengutronix.de>
Date: Mon, 5 Feb 2024 18:32:42 +0100
From: Marco Felsch <m.felsch@...gutronix.de>
To: Guenter Roeck <linux@...ck-us.net>
Cc: "Dr. David Alan Gilbert" <linux@...blig.org>,
	gregkh@...uxfoundation.org, robh+dt@...nel.org,
	krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
	heikki.krogerus@...ux.intel.com, linux-usb@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	kernel@...gutronix.de
Subject: Re: [PATCH 4/4] usb: typec: tcpci: add support to set connector
 orientation

On 24-02-05, Guenter Roeck wrote:
> On 2/5/24 08:54, Marco Felsch wrote:
> > Hi David,
> > 
> > On 24-02-05, Dr. David Alan Gilbert wrote:
> > > * Marco Felsch (m.felsch@...gutronix.de) wrote:
> > > > This add the support to set the optional connector orientation bit which
> > > > is part of the optional CONFIG_STANDARD_OUTPUT register 0x18 [1]. This
> > > > allows system designers to connect the tcpc orientation pin directly to
> > > > the 2:1 ss-mux.
> > > > 
> > > > [1] https://www.usb.org/sites/default/files/documents/usb-port_controller_specification_rev2.0_v1.0_0.pdf
> > > > 
> > > > Signed-off-by: Marco Felsch <m.felsch@...gutronix.de>
> > > > ---
> > > >   drivers/usb/typec/tcpm/tcpci.c | 43 ++++++++++++++++++++++++++++++++++
> > > >   include/linux/usb/tcpci.h      |  8 +++++++
> > > >   2 files changed, 51 insertions(+)
> > > > 
> > > > diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
> > > > index 7118551827f6..7ce9d4923bc7 100644
> > > > --- a/drivers/usb/typec/tcpm/tcpci.c
> > > > +++ b/drivers/usb/typec/tcpm/tcpci.c
> > > > @@ -67,6 +67,18 @@ static int tcpci_write16(struct tcpci *tcpci, unsigned int reg, u16 val)
> > > >   	return regmap_raw_write(tcpci->regmap, reg, &val, sizeof(u16));
> > > >   }
> > > > +static bool tcpci_check_std_output_cap(struct regmap *regmap, u8 mask)
> > > > +{
> > > > +	unsigned int reg;
> > > > +	int ret;
> > > > +
> > > > +	ret = regmap_read(regmap, TCPC_STD_OUTPUT_CAP, &reg);
> > > > +	if (ret < 0)
> > > > +		return ret;
> > > > +
> > > > +	return (reg & mask) == mask;
> > > > +}
> > > > +
> > > >   static int tcpci_set_cc(struct tcpc_dev *tcpc, enum typec_cc_status cc)
> > > >   {
> > > >   	struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
> > > > @@ -301,6 +313,27 @@ static int tcpci_set_polarity(struct tcpc_dev *tcpc,
> > > >   			   TCPC_TCPC_CTRL_ORIENTATION : 0);
> > > >   }
> > > > +static int tcpci_set_orientation(struct tcpc_dev *tcpc,
> > > > +				 enum typec_orientation orientation)
> > > > +{
> > > > +	struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
> > > > +	unsigned int reg;
> > > > +
> > > > +	switch (orientation) {
> > > > +	case TYPEC_ORIENTATION_NONE:
> > > > +		/* We can't put a single output into high impedance */
> > > 
> > > Is that intended to be a fallthrough? If so I guess it needs
> > > marking as such with a
> > >                  fallthrough;
> > 
> > You need to add it if there is code in between. Since there is no code,
> > just this comment, it shouldn't be necessary.
> > 
> 
> Still, I think it would be desirable here to clarify that this
> is not a lost return but intentionally sets
> TCPC_CONFIG_STD_OUTPUT_ORIENTATION_NORMAL.

Sure, I will adapt it once the complete patchset is reviewed.

Regards,
  Marco

> Guenter
> 
> > Regards,
> >    Marco
> > 
> > > 
> > > Dave
> > > 
> > > > +	case TYPEC_ORIENTATION_NORMAL:
> > > > +		reg = TCPC_CONFIG_STD_OUTPUT_ORIENTATION_NORMAL;
> > > > +		break;
> > > > +	case TYPEC_ORIENTATION_REVERSE:
> > > > +		reg = TCPC_CONFIG_STD_OUTPUT_ORIENTATION_FLIPPED;
> > > > +		break;
> > > > +	}
> > > > +
> > > > +	return regmap_update_bits(tcpci->regmap, TCPC_CONFIG_STD_OUTPUT,
> > > > +				  TCPC_CONFIG_STD_OUTPUT_ORIENTATION_MASK, reg);
> > > > +}
> > > > +
> > > >   static void tcpci_set_partner_usb_comm_capable(struct tcpc_dev *tcpc, bool capable)
> > > >   {
> > > >   	struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
> > > > @@ -808,6 +841,9 @@ struct tcpci *tcpci_register_port(struct device *dev, struct tcpci_data *data)
> > > >   	if (tcpci->data->vbus_vsafe0v)
> > > >   		tcpci->tcpc.is_vbus_vsafe0v = tcpci_is_vbus_vsafe0v;
> > > > +	if (tcpci->data->set_orientation)
> > > > +		tcpci->tcpc.set_orientation = tcpci_set_orientation;
> > > > +
> > > >   	err = tcpci_parse_config(tcpci);
> > > >   	if (err < 0)
> > > >   		return ERR_PTR(err);
> > > > @@ -851,6 +887,13 @@ static int tcpci_probe(struct i2c_client *client)
> > > >   	if (err < 0)
> > > >   		return err;
> > > > +	err = tcpci_check_std_output_cap(chip->data.regmap,
> > > > +					 TCPC_STD_OUTPUT_CAP_ORIENTATION);
> > > > +	if (err < 0)
> > > > +		return err;
> > > > +
> > > > +	chip->data.set_orientation = err;
> > > > +
> > > >   	chip->tcpci = tcpci_register_port(&client->dev, &chip->data);
> > > >   	if (IS_ERR(chip->tcpci))
> > > >   		return PTR_ERR(chip->tcpci);
> > > > diff --git a/include/linux/usb/tcpci.h b/include/linux/usb/tcpci.h
> > > > index 467e8045e9f8..f2bfb4250366 100644
> > > > --- a/include/linux/usb/tcpci.h
> > > > +++ b/include/linux/usb/tcpci.h
> > > > @@ -47,6 +47,9 @@
> > > >   #define TCPC_SINK_FAST_ROLE_SWAP	BIT(0)
> > > >   #define TCPC_CONFIG_STD_OUTPUT		0x18
> > > > +#define TCPC_CONFIG_STD_OUTPUT_ORIENTATION_MASK		BIT(0)
> > > > +#define TCPC_CONFIG_STD_OUTPUT_ORIENTATION_NORMAL	0
> > > > +#define TCPC_CONFIG_STD_OUTPUT_ORIENTATION_FLIPPED	1
> > > >   #define TCPC_TCPC_CTRL			0x19
> > > >   #define TCPC_TCPC_CTRL_ORIENTATION	BIT(0)
> > > > @@ -127,6 +130,7 @@
> > > >   #define TCPC_DEV_CAP_2			0x26
> > > >   #define TCPC_STD_INPUT_CAP		0x28
> > > >   #define TCPC_STD_OUTPUT_CAP		0x29
> > > > +#define TCPC_STD_OUTPUT_CAP_ORIENTATION	BIT(0)
> > > >   #define TCPC_MSG_HDR_INFO		0x2e
> > > >   #define TCPC_MSG_HDR_INFO_DATA_ROLE	BIT(3)
> > > > @@ -198,12 +202,16 @@ struct tcpci;
> > > >    *		Chip level drivers are expected to check for contaminant and call
> > > >    *		tcpm_clean_port when the port is clean to put the port back into
> > > >    *		toggling state.
> > > > + * @set_orientation:
> > > > + *		Optional; Enable setting the connector orientation
> > > > + *		CONFIG_STANDARD_OUTPUT (0x18) bit0.
> > > >    */
> > > >   struct tcpci_data {
> > > >   	struct regmap *regmap;
> > > >   	unsigned char TX_BUF_BYTE_x_hidden:1;
> > > >   	unsigned char auto_discharge_disconnect:1;
> > > >   	unsigned char vbus_vsafe0v:1;
> > > > +	unsigned char set_orientation:1;
> > > >   	int (*init)(struct tcpci *tcpci, struct tcpci_data *data);
> > > >   	int (*set_vconn)(struct tcpci *tcpci, struct tcpci_data *data,
> > > > -- 
> > > > 2.39.2
> > > > 
> > > > 
> > > -- 
> > >   -----Open up your eyes, open up your mind, open up your code -------
> > > / Dr. David Alan Gilbert    |       Running GNU/Linux       | Happy  \
> > > \        dave @ treblig.org |                               | In Hex /
> > >   \ _________________________|_____ http://www.treblig.org   |_______/
> > > 
> 
>